What it is: A carefully calculated regimen that heavily reduces the number of calories ingested per day.
Why it works: When a person ingests fewer calories, cells are signaled to become less active—like a car driving fewer miles, they are protected from wear and tear, slowing the body’s aging process. Also reduces risks for cardiovascular disease and diabetes.
What the experts say: “There have been a lot of studies in humans and animals which show that it doesn’t necessarily concern what you eat but the amount of what you eat,” says Christy Carter, a professor at the University of Florida’s Department of Aging and Geriatric Research. “And so that’s the most important thing for extending longevity.” Though only preliminary experiments have been conducted on humans—avid supporters of this technique rely heavily on tests done on mice and rats—there’s general confidence that this strict regimen could let people live a little longer. Eric Ravussin, who studies human health and performance at Louisiana’s Pennington Biomedical Center,
quantified the effect: “Eat 15 percent less starting at age 25 and you might add 4.5 years to your life.”